1. Field of the Invention
The present invention relates to a flexible antenna module for wireless energy transmission; and more particularly to a flexible antenna module for wireless energy transmission, which enables the antenna's size adjustable to conform an individual's outer portion.
2. Description of the Related Art
Electrical stimulator combines the principles of Chinese traditional Point Percussion Therapy and western TENS (Transcutaneous Electrical Nerve Stimulation). The stimulator uses micro electric current to stimulate specific acupuncture points to achieve the health care effect. That is it can stimulate the self-cure mechanism of the body with an electric current having suitable intensity and frequency continuously, gently stimulating the nerve, the muscle and the cell. On clinical uses, the method of treatment is divided into the Transcutaneous Electrical Nerve Stimulation (TENS) and the Electrical Muscle Stimulation (EMS).
The electrical stimulation has been widely utilized for the function of recovery. Recently, as a result of the breakthrough of the micro electron technology, the micro mechanical and electrical technology, the biological material and the biological compatible seal technology, the electrical stimulator tends to have a small and implanted form.
FIG. 1 is a conventional implanted electrical stimulator comprising an in vivo electrical stimulating module 10 and an in vitro energy-transmitting module 12. The in vivo electrical stimulating module 10 includes a circuit board 100; an in vivo energy-transmitting coil 102 and a pair of positive/negative electrodes 104 provided on the circuit board 100 and a biological compatible polymer layer 106 covering the whole in vivo electrical stimulating module 10. The in vitro energy-transmitting module 12 includes an in vitro control module 120 and an in vitro energy-transmitting coil 122. The in vitro control module 120 will drive the in vitro energy-transmitting coil 122 to emit wireless energy. The wireless energy will be received by the in vivo energy-transmitting coil 102 and converted by the circuit board 100 into a voltage source. The converted voltage source will be applied on the positive/negative electrodes 104 to generate an electrical stimulating current.
As mentioned above, the conventional implanted electrical stimulator transmits the energy from an external antenna module to an in vivo implanted electrical stimulating element via radio frequency (RF) and receive the energy by an internal electronic component to automatically generate an electrical stimulation, rather than stimulating the nervous muscle with an electrical line penetrating through the skin, thus can reduce the probability of wound infection. However, the energy needed by the implanted electrical stimulating device is unidirectionally transmitted into the implanted electrical stimulating device via a fixed-size antenna. That is, the energy is transmitted to the in vivo electrical stimulating module via an external energy-transmitting antenna to stimulate the nervous muscle. In operation, this energy-transmitting method may suffer from the displacement of the implanted electrical stimulating element or the electromagnetic interference from surrounding environment and thus change the properties of the energy-transmitting circuit, thereby causing to transmit excessive energy to result in heat-generating from the implanted electrical stimulating element, or causing to transmit too little energy to result in abnormal operation or even malfunction, thereby further causing unnecessary damage to the human body. In addition, effective detection of the position of the implanted electrical stimulating element and provision of effective energy-transmission are also general issues encountered for the implanted electrical stimulators.
In brief, the method for energy transmission of the conventional implanted electrical stimulator has the following disadvantages:                1. The antenna's size is fixed, and unsafe and un-comfortable in utilization.        2. The exact position of the implanted electrical stimulator is not easy to detect.        3. Control of the power transmission does not come easy.        4. Properties of the energy transmission circuit easily suffer from electromagnetic interference from surrounding environment.        
Accordingly, there is an improved antenna technique for energy transmission provided.